Why do you buy a game if you have no idea if its going to be any good? I personally NEVER preordred games, unless I can play a demo. CoD:MW3 is going be a copy of every other new Call of Duty games (MW2, BO, CoD4) so there's your game. I cant see a good reason to buy this because its gonna be se exact same shit as every modern CoD: they just make a new CoD every year with slightly buffed graphics and some new stuff in it.
I think/hope that BO was the turning point where people realize that nothing will change in CoD after CoD4, which was a good game with promod, but ofcourse you know nothing of that since you're probly a console gamer.